“Find the CULPRIT!” Challenge

It’s been some time since I’ve posted my after school club challenges.
This week I decided to challenge the students to find out who scribbled on a piece of paper.

Materials:
Running alcohol
5 Different types of pens (I had 4 black ink pens and 1 blue ink pen)
Recording worksheet
Pencils
Coffee filters

Investigation Method:
First, I showed the students the paper with all the scribbles. They knew I had done it immediately, but they didn’t know which pen I used to make the scribbles. So, to get them to begin their own investigation, I demonstrated to them how to get the colors out of the inks.
Take a pen – Draw a circle on the coffee filter – Fill in the circle by coloring it in lightly so that the coffee filter doesn’t rip – take a pipette, get some rubbing alcohol – Drop 2 or 3 drops of the rubbing alcohol on the ink – See what happens to the blank inkThe students tested 5 different pens then determined which pen came closest to the paper with the scribbles.

Here are some of the pictures during our investigation:

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